Diazotype materials derived from aryl diazo sulfones



Patented Mar. 29, 1949 .DIAZOTYPEMATERIALS DERIVED FRO]! ABYL DIAZO SULFONES JosephLSprnngandWillyA. la assignors 86mm. GeneralAnilinell'ilmcoh poration, New York, N. Y., a corporation of Delaware No Drawing. Application July 2, 1941 Serial This invention relates to photoprinting materials for the direct reproduction of positive prints from positive originals and negative prints from negative originals. More particularly, it relates to a photoprinting material comprising a light sensitive element which will decompose upon exposure to light and in. its undecomposed form will couple with an azo dye coupling component to form a dye image.

Many processes have been suggested for the production of photoprinting material of this type, such processes diilerlng principally in the chemical used as the light sensitive element or in the manner of developing the dye image. The most widely known and successful of these processes are those which are based upon the light sensitivity of aromatic diazo compounds. Other processes of less extensive use are based upon the light sensitivity of the leuco compounds of vat dyestuifs; processes based upon the oxidizing action of o-nitro groups in aromatic systems having aliphatic side chains as, for instance, o-nitrophenol lactic acid methyl ketone; and processes based upon the light sensitivity of the o-nitrodiaminotriphenyl-methane bases. With the exception of the process based upon the light sensitivity of aromatic diazo compounds, these photoprinting processes for the reproduction of positive copies have found little commercial adaptability, either because of the instab lity of the compounds employed or the difliculty of developing the dye image from the undecomposed light sensitive material.

There are, in general, two processes in use based upon the lightsensitivity of aromatic diazo compounds. These are designated as, respectively, the one-component or wet development process and the two-component or dry development process. In the one-component process, the aromatic diazo compound is incorporated into the light sensitive layer of thecar rier, which may be opaque or transparentized paper, films such as cellulose ester or cellulose ether film, regenerated cellulose bodies, ceram c surfaces, glass, metallic or wood surfaces, and after exposure under the orig nal pa tern. to be copied the undecomposed aromat c diazo compound is developed by contacting the exposed layer with a solut on of the coupling component necessary to produce the ultimately desired image. Since most of these aromatic diazo com pounds are developed in alkal ne solution, the developing solution containing the coupling component should be alkaline. In some cases. however, diazo compounds are employed which are 8 Claims. (Cl. 95-7) developable in acid solution and in such cases the solution of the coupler will be acid. In the two-component process, the aromatic diazo compound and the coupling component necessary to 1 produce the dye image are both incorporated in the light sensitive layer on the carrier. In this case, development of the dye image is eifected after exposure by contacting the exposed light sensitive layer with ammonia fumes. For optimum results in the two-component process, it is necessary to limit the selection of diazo compounds to those which will be inert to reaction with the coupling component while in the coating solution and the light sensitive layer prior to development. The most satisfactory diazo compounds for this purpose have been found to be those which are derived from aromatic p-diamines and o-aminonaphthols; A few others have been found suitable, particularly when addition agents are employed which tend to retard the coupling function. For the most part, however, premature coupling of the dye components takes place when other types of diazo compounds are used.

In all photoprinting processes it is highly desirable to produce a copy which will have a clear white background or a transparent background, as in the case of film carriers, in. order that the contrast shall not be impaired. In the case of the aromatic diazo compounds, premature coupling of the diazo compound and the coupling component will produce such discoloration in the background and even in the case of the most desirable diazo compounds selected from the aromatic p-diamines and o-aminonaphthols premature coupling cannot be completely avoided, especially when long periods of storage are required. Processes have been suggested for increasing the storage life of such photoprinting material, which processes depend upon the addition of retard ng agents to the sensitizing solution used in producing the light sensitive layer or coating on the carrier.

In United States Patent 2,411,811, there is described a class of compounds, namely N-n tro o- N-arylamides, whichmay be used as the light sensit ve element in place of aromatic d azo compounds. The decomposltion of the N-nitroso- N-arylamides of said patent by exposure to light and the coupling reaction of those compounds with azo dye coupling components are similar to the decomposition and coupling of aromatic diazo compounds. Thus they are decomposed by exposure to light to compounds which will no longer couple to form an azo dye, but if not 'diethylamino, ,6,fi'-dihydroxyethylamino 2-benzothiazolylamino so decomposed they will couple to form an azo ye in the presence of an alkaline medium. They will not couple, however, in. the absence or an alkaline medium and hence can be stored indefinitely as a two-component system in a diazotype layer which has been made slightly acid by the addition of weak acids. Premature coupling oi. the dye components will not take place and hence background color will not be developed in the diazotype print.

We have now discovered another class of compounds which can be used as the light sensitive element in the preparation of positive diazotype reproduction photoprinting material which are capable of forming dye images upon development with azo dye coupling components in alkaline medium. This class of compounds may be designated as the diazo sulfones. They are incapable of coupling with azo dye coupling components in the absence of the alkaline coupling medium and hence, like the N-nitroso-N-arylamides of Patent 2,411,811, two-component light sensitive layers produced from these diazo sultones can be stored indefinitely without danger oi precoupling of the dye components taking place under ordinary conditions of storage.

' no longer react with coupling components to produce azo dyes, thus insuring the absence of the image color in the high-light or background areas which is sometimes formed in diazotypes using aromatic diazo compounds as the light sensitive elements due to incomplete light decomposition of the diazo compound. In the areas of a diazotype photoprint paper which have not been exposed to light due to the masking effeet of the lines of the original pattern or picture, the diazo sulfones of this invention will couple readily with azo dye coupling components in the presence of an alkaline medium, such as ammonia iumes, to produce an azo dye image in any desired color.

It has been found that the light sensitive diazo sulfones which are suitable for the purpose of this invention belong to the class represented by the following general formula RN=N-SO:R'

where R represents a radical derived from a compound having an aromatic character such as benzene, naphthalene, anthracene, quinoline, carbazole, indole and the like, and R represents a radical derived from a compound having an aromatic character as above or from a compound having an aliphatic character such as methane, ethane, butane, pentane, hexane, cyclohexane, methylcyclohexane, octane, decane, dodecane, hexadecane, octadecane and the like. In one preferred embodiment of the invention, the diazo sulfones may have certain substituents on the aromatic nuclei, R. These preferred diazo sulfones may be represented by the general formula X-RN=NSO2-R' wherein R and B have the same meaning as above and X represents a member of the class consisting of alkylamino, such as methylamino, and N-methyl N-p-hydroxyethylamino groups; arylamino, such as phenylamino; aralkylamino. such as benzylamino; heterocyclic amino, such as and Z-pyridylamino; alkyl, such as methyl, ethyl, butyl, lauryl and octadecyl; alkoxy, such as methoxy and butoxy;

4 aryioxy, such as phenoxy; aliphatic acylamino, such as acetamido; and aromatic acylamino, such as benzamido.

In another preferred embodiment, the diazo sulfones may be represented by the general formula wherein R and R represent radicals derived irmn compounds of an aromatic character as defined above, x has the same meaning as above and Y represents a member of the class consisting of allwlamino, such as methylamino, diethylamino, p,p'-dihydroxyethylamino and N-methyl- N-fl-hydroxyethylamino groups; arylamino, such as phenylamino; aralkylamino, such as benzylamino; heterocyclic amino, such as 2-benzothiazolylamino and 2-pyridylamino; alkyl, such as methyl, ethyl, butyl, lauryl and octadecyl; alkoxy, such as methoxy and butoxy; aryloxy, such as phenoxy; aliphatic acylamino, such as acetamido; and aromatic acylamino,. such as benzamido. It has been found that in those compounds in which Y is an electropositive substituent, such as amino, acylamino, alkoxy or the like, the thermal stability of the diazo sulfone compound is better. Also X and Y may contain solubilizing groups such as sulfo, carboxy and polyoxyethylene groups.

The diazo sulfones, in general, are prepared by the reaction of a diazo compound with a sulilnic acid, oxidation of a fl-aryl sulfonhydrazide, condensation of a diazonium salt with a sulfonamide or decomposition of a diazo thiosulfate. Schematic reactions for these processes of preparing the diazo sulfones are as follows:

1. Condensation of a diazo compound with a sulfinic acid (a) RN=N+X-+R'--SOQH RN=N-SO2R'+HX (b) RN=N--CN+R'SO2H R-N=NSO2R +HCN (c) R-N=NNH-R"+2R'SOzH- R--N=NSO2R'+R' NH:+ (SOzR) 2. Oxidation of ,B-arylsulfonhydrazide R-NH-NEL-SOJV. n-N=N-so,a'

H30 3. Condensation of a diazonium salt with a sulfonamide R-N=N+X-+RSOzNI-Iz RN3+HX+R'SO2H R-N=N+X-+R'SO:H

RN=N-SOzR'+HX 4. Decomposition of a diazothiosulionate RN=N+X-+KSSO:R'

R--N=N+-(SSO2R) R--N=N+( S-SO:R)

RN=NSOzR'+S The most suitable method of preparation was found to be the reaction of a diazo compound with a sulflnic acid and this reaction was used to prepare the following diazo sulfones which are given as examples of light sensitive diazo sulfones suitable for the process of this invention.

Examples of suitable aryldlazosulfones include diphenylamine 4 diazo (p-aminophenyl) -sulione, 4--(N-ethyl-N-benzylamino) -benzenedlazo- (p-aminophenyl) -sulfone, 4-morpholinobenzenediazo- (p-aminophenyl) -sulfone, p- (N-methyl-N- fl-hydroxyethylamino) -benzenediazo (p-aminophenyl) -sulfone, 2,5-dimethoxy 4 benzamidobenzenediazo- (p-acetaminophenyl) -sulfone, 2,5- dimethoxy 4 benzamidobenzenediazo- (p-methtile amines or solutions of mild alkalis,

oxyphenyl) -sulfone, 2 methyl methoxy-4- benzamidobenzenediazo (p acetaminophenyl) sulione, 2 methyl 5 methoxy 4 benz'amidobenzenediazo (p-ethoxyphenyl) sulione, p-diethylaminobenzenediazo (p aminophenyl) -sultone, 4 (2,6 dichlorobenzylamino) benzenedlazo (p-aminophenyl) sulfone, 3-phenoxy-4- (2',6' dichlorobenzylamino) benzenediazo-(paminophenyl) sulfone, 2,5 dimethoxy-4-benzamidobenzenediazo (methyl) sulfone, 2,5-dimethoxy 4 benzamidobenzenediazo (ethyl) sulione, 2,5 dimethoxy 4 benzamidobenzene diazo-(benzyl) -sulfone, 2,5-dimethoxy 4 benzam'idobenzenediazo- (decyl) -su1fone, 4-dimethylaminobenzenediazo-(p-aminophenyl) -sulfone, 4- ethylamino 3 methylbenzenediazo (p-aminophenyl) -sulfone, 4-dimethylamino-2-methylbenzenediazo-(p-aminophenyl) -sulfone, 4-diethylamino-2-ethoxybenzenediazo (p-aminophenyl) sulfone, 4-dimethylamino-2-ethoxybenzenediazop-aminophenyl) -sul.fone, 4-ethylpropylamino-2- methoxybenzenediazo (p-aminophenyl) -sulfone, 4 ethylbutylamino 2 methoxybenzenediazo- (p-aminophenyl) -sulfone, 4-(N-p-hydroxyethyl- N-ethylamino) benzenediazo- (p-aminophenyl) sulfone, 4 benzylamino 2,5 diethoxybenzenediazo- (p-aminophenyl) -sulfone and the like.

Examples of coupling components which may be utilized with the diazo suliones in this process are 2,3-dihydroxynaphthalene, resorcinol, phloroglucinol, p-naphthol, a-naphthol, 3,5-dimethylphenol, 2,4-dihydroxybenzenesulfonamide, 1 phenyl-3-methylpyrazolone-5, acetoacetanilide, 5-methyl resorcinol, 1-dimethylaminomethyl-2- naphthol, 3-(fl-dimethylaminoethoxy) -naphthol- 2, esters of phloroglueinol monocarboxylic acid, and the couplers disclosed in United States Patents 1,822,065, 1,989,065, 2,150,565, 2,196,950, 2,212,959, 2,333,038, 2,245,628, 2,246,425 and 2,286,656. a

In its preferred embodiment, the process of this invention is carried out by coating a suitable base, such as paper, a cellulose ester, cellulose ether or regenerated cellulose film, a ceramic material, a textile material, a gelatinized surface or a metallic surface with a coating preparation containing the diazo sulfone compound. an azo dye coupling component such as one of the coupling components mentioned above, a mild acid such as citric, tartaric, acetic, oxalic, maleic acid or a strong acid such as sulfosalicylic acid and a solvent. The diazosulione, unlike the corresponding diazonium salts, are soluble in water-miscible organic solvents such as acetone, methyl ethyl ketone, methanol, ethanol, isopropanol and the coating mixture can, therefore, be applied in the form of solutions in such solvents or aqueous mixtures thereof. The coating mixtures can also be applied to the base in the form of their water solutions if the diazo sulfone contains water solubilizing groups or if the coating mixture contains a hydrotropic reagent, such as sodium toluenesulfonate, potassium xylenesulfonate, sodium cymenesulfonate, sodium salicylate and the like. The coating of the selected support is efiected in the usual manner by applying the coating solution to the surface of the carrier with a trough and doctor blade or by spraying. The coated material is then dried and exposed under original positive or negative picture or drawing and developed by treatment with ammonia vapor or other suitable alkaline materials, such as v0 1 e coating medium or vehicle for the application of the light sensitive layer, in addition to water and organic solvents, may be an aqueous gelatin or a resinous material such as cellulose acetate hydrogen phthalate suitably liquefied by organic solvents or otherwise for coating purposes.

In the development of the undecomposed diazo sulfone with the coupling component present in the light sensitive layer or applied thereto as part of the developing agent, it is observed that the coupling reaction, unlike the case or the related sulionic acid derivatives of diazonium salts (RN==N-S0z0 alkali metal) will take place without the incidence of ultraviolet light. The coupling reaction in the case of the diazo suli'ones is a direct action which takes place readily in the presence of proper alkaline coupling medium. The exact mechanism of the coupling reaction is not definitely known. It is believed, however; that an active methylene group of the coupling component adds to the polarized azo linkage in the diazo sulfone and that a suliinic acid is subsequently split out to give the azo dye. The probable scheme of the reaction is as follows:

The practice of this invention may be best understood by reference to the following specific examples which are presented as illustrative of the process involved and not as limitations of the scope of the invention. Unless otherwise stated, the parts given are by weight.

Example 1 A diazotype paper stock was coated with a coating solution of the following composition 1.0 gram 2,5-diethoxy-4-benzamidobenzenediazo (p-acetamidophenyl) -sulfone O CzHe I c-mc ONHQNm-S OQNHC 0 on,

1.0 gram 2,3-dihydroxynaphthalene 5.0 grams oxalic acid 50 cc. acetone The thus coated paper was allowed to dry and was then exposed under a pattern to ultraviolet light radiations. The exposed sensitized paper was then passed through an atmosphere of ammonia vapors. The original pattern was developed in a clear purple dye image on a white background.

Upon coating the same solution on a sheet of gelatinized film base instead of the paper used in this example, drying, exposing and developing in the same manner as above, a transparency having a purple azo dye image of the pattern was produced.

The 2,5-diethoxy 4 benzamidobenzsnediazo- (p-acetamidophenyl) -sulfone may be obtained by diazotizing a suspension of 8.4 grams (0.025 mol) of 2,5-diethoxyi-benzamidoaniline hydrochloride in 2.0 cc. concentrated hydrochloric acid, 8.0 cc. formic acid and cc. water with a solution of 1.8 grams (0.026 mol) sodium nitrite in 10 cc. water. The excess nitrous acid is destroyed with suliamic acid and the filtered diazonium salt solution added to a solution of 5.2grams (0.026 mol) of p-acetamidobenzene sulfinic acid and 1.62 grams (0.013 mol) sodium carbonate monohydrate in 100 cc. water. The orange colored precipitate is removed by filtration, washed well with water and air dried. The product weighs 11.3

grams (89%) and melts with decomposition at approximately 110 C.

Example 2 A diazotype paper stock was coated with a resinous coating solution of the following composition:

1.0 gram 2,5-diethoxy-4-benzamidobenzenediazo (p-acetamidophenyl) -sulfone 1.0 gram 2,3-dihydroxynaphthalene 5.0 grams maleic acid r 10.0 grams cellulose acetate hydrogen phthalate 50.0 cc. acetone The thus coated paper was dried and then exposed under a pattern to ultraviolet light radiations. The exposed sensitized paper was then passed through an atmosphere of ammonia vapors. The original pattern was developed in a clear purple dye image on a transparent resinous layer having the white surface of the paper as a background in those areas where the diazo sulfone had been decomposed and rendered inactive in the coupling reaction.

Example 3 A coating solution for a diazotype was made up as follows:

0.22 gram 4-diethy1aminobenzenediazo (p-aminophenyl) -sulf one 0.32 gram 2,3-dihydroxynaphthalene 8.0 grams maleic acid 55.0 cc. acetone were added to a solution of 80.0 grams cellulose acetate butyrate in 400.0 cc. acetone.

The combined solution was coated on a diazotype paper stock and allowed to dry. The thus diazotype sensitized paper consisting of a resinous layer of the cellulose acetate butyrate carrying the diazosulfone and the coupling component on the paper support was exposed under a positive original pattern and the image developed after exposure by contacting the exposed surface with ammonia vapors. The image of the original was developed to a purple azo dye.

The 4 -diethylaminobenzenediazo (p-amlnophenyl) -sulfone of this example may be obtained as follows. A solution of 20.0 grams (0.1 mol) p-diethylaminoaniline hydrochloride in 75.0 00. water and 20.0 cc. concentrated hydrochloric acid is diazotized with a solution of 6.9 grams (0.1 mol) sodium nitrite in 75.0 cc. water. This solution is then poured into a solution of 15.7 grams (0.1 mol) 4-aminobenzene sulflnic acid, 6.2 grams (0.05 mol) sodium carbonate monohydrate, 41.0 grams (0.3 mol) sodium acetate dihydrate and 250.0 cc. water. The resulting mixture is allowed to remain overnight in a refrigerator and the following day the orange color precipitate is removed by filtration,

washed with water and dried. The product, weighing 29.5 grams, melts over a wide range with decomposition.

Ezample 4 A diazotype coating solution was prepared in the following manner:

0.11 gram (0.00033 mol) 4-diethylaminobenzenediazo (p-aminophenyl) -sulfone 0.11 gram (0.001' mol) resorcinol 4.0 grams citric acid in 25.0 cc. acetone Example 5 A diazotype coating solution was prepared in the following manner:

0.11 gram l-diethylaminobenzenediazo (p-aminophenyl) -sulfone 0.162 gram (0.001 mol) phloroglucinol dihydrate 4.0 grams citric acid in 25.0 cc. acetone were added to a solution of 40.0 grams cellulose acetate butyrate in 200.0 cc. acetone.

The combined solution was coated on a sheet of diazotype paper stock and dried. The thus sensitized paper was exposed under a positive original design and processed in the same man= ner as in the case of Example 4. The image of the original was reproduced in a brown azo dye.

Example 6 A diazotype coating solution was prepared as follows:

0.11 gr d-diethylaminobenzenediazo (p-amin phenyl) -sone 0.17% gram (0.001 mol) 1-phenyl-3-methyl pyraz= clone-5 4.0 gr citric acid in 25.0 cc. acetone were mixed. and added to a solution of 40.0 grams cellulose acetate butyrate in 200.0 cc. acetone.

The combined solution was coated on a sheet of diazotype paper stock and dried. The thus sensitized diazotype was exposed under a positive original design and processed in the same manner as in the case of Example 4. A redorange azo dye image was produced.

Example 7 A diazotype coating solution was prepared as follows:

0.11 gram d-diethylaminobenzenediazo (p-aminophenyl) -sulfone 0.11 gram (0.001 mol) acetoacetanilide 4.0 grams citric acid 25.0 cc. acetone were mixed and added to a solution of 40.0 grams cellulose acetate butyrate in 200.0 cc. acetone.

The combined solution was coated on a sheet of diazotype paper stock and dried. The thus sensitized diazotype was exposed under a positive original design and processed in the same manner as in Example 4. A yellow azo dye image was produced.

Example 8 A diazotype coating solution was made up in the following manner:

0.17 gram (0.00033 mol) 2,5-diethoxy-4-benzamido benzenediazo (p-acetamidophenyl) -sultone 0.16 gram (0.001 mol) 2,3-dihydroxynaphthalene 4.0 grams citric acid were added to 25.0 cc. acetone. This solution was then added to a solution of 40.0 grams cellulose acetate butyrate in 200.0 cc. acetone.

The combined solution was coated on a sheet of diazotype paper stock and dried. It was then exposed under a positive original design to ultraviolet radiations and developed by passing the exposed surface through a chamber containing ammonia fumes with which the exposed surface was brought into contact. The image of the original was reproduced in a reddish-purple azo dye.

Upon substituting 0.11 gram resorcinol for the 2,3-dihydroxynaphthalene coupler of this example and processing in the same manner, a brown azo dye image will be produced.

Upon substituting 0.162 gram phloroglucinol dihydrate for the coupler, a brown azo dye image will also be produced.

Upon substituting 0.174 gram 1-phenyl-3- methyl pyrazolone-5 for the coupler, a yelloworange azo dye image will be produced.

Upon substituting 0.177 gram acetoacetanilide a yellow azo dye image will be produced.

in 25 cc. of 40% aqueous technical sodium xylene sulfonate was diluted with 25 cc. water and to the resulting solution was added 0.16 gram (0.001 mol) 2,3-dihydroxynaphthalene and 0.5 citric acid. The sensitized solution was coated on paper base and was exposed and processed as in the previous examples. A blue azo dye image was produced.

Example Same as Example 9 except that 0.1? gram of 2.5-diethoxy-4-benzamido benzene diaao-(d-aeetamidophenyl) -sulfone was used as the light-sensitive diaso component. A purple azo dye image was produced.

Having now set forth and fully descrimd our invention and having illustrated the proper manner in which to Perform it. what we desire to protect by Letters Patent and therefore claim as '1. Dlaaotype photoprinting materials compris- 10 ing as the light sensitive element a light sensitive diazo sulfone of the following formula wherein R is an aromatic radical and R is a member of the group consisting of aromatic and aliphatic radicals.

2. Diazotype photoprinting materials comprising as the light sensitive element a light sensitive diazo sulfone of the following formula wherein R and R are aromatic radicals.

3. Diazotype photoprinting materials comprising as the light sensitive element a light sensitive diazo sulfone of the following formula wherein R and R are aromatic radicals and an azo dye coupling component.

4. Diazotype photoprinting materials comprising a light sensitive layer on a suitable carrier, said light sensitive layer containing as the light sensitive element a diazo sulfone of the following formula wherein R and R are aromatic radicals and an azo dye coupling component.

5. Diazotype photoprinting materials comprising a resinous layer on a paper carrier, said resinous layer containing as a light sensitive element a diazo sulfone of the following formula wherein R and R are aromatic radicals together with an azo dye coupling component.

6. Diazotype photoprinting materials comprising a light sensitive layer on a. suitable carrier, said light sensitive layer containing 2,5- diethoxy- 4-benzamidodiazo-(p-acetamidophenyl) sulfone as the light sensitive element and an azo dye coupling component.

'I. Diazotype photoprinting materials comprising a light sensitive layer on a suitable carrier. said light sensitive layer containing 4-diethylaminobenzenediazo-(p-aminophenyl)-sulfone as the light sensitive element and an azo dye coupling component.

8. Dlaaotype photoprinting materials comprising a light sensitive layer on a suitable carrier, said light sensitive layer containing d-morpholinobenzenediaso-(p-aminophenyll-sulfone as the light sensitive element and an azo dye coupling component.

JOSEPH A. SPRUNG. WILLY A. SCHMIDT.

REFERENCES CITED The following references are of record in the file of this patent: 

